The need sometimes arises for a self contained small power generating unit providing relatively small amounts of electrical power which is relatively immune to hostile environments. One such application is in aircraft.
In such aircraft, it has been traditional to supply both electrical power and electrical control signals to electrohydraulic servovalves for positioning aircraft control surfaces through wire harnesses run throughout the aircraft. Such wiring renders the aircraft susceptible to hostile environments such as lightning and the like. In some instances pursuant to current practice, electrohydraulic servovalves are controlled by light signals as opposed to electrical signals. However, the power required by the amplifiers for driving the electrohydraulic servovalves must be obtained other than from a central power source to preclude long runs of electrical wiring. By providing an isolated electric power source ("source", hereafter) capable of running the amplifier at the hydraulic actuator which, for example, moves the control surfaces or the like, the need for long runs of electrical wiring can be eliminated. Such thus reduces the susceptibility of the aircraft to failure from hostile environments.
The prior art known to applicants consists of U.S. Pat. Nos. 3,094,635, 3,119,940 and 3,568,704.